Au nanoparticle-decorated aragonite microdumbbells for enhanced antibacterial and anticancer activities.

The present work reports the very first hydrothermal synthesis of 100% triclinic phase pure aragonite (A1) with microdumbbell microstructural architecture and Au Nanoparticle-decorated (AuNP-decorated) aragonites (A2, A3 and A4) with spherical, pentagonal/hexagonal and agglomerated AuNP-decorated microdumbbells having triclinic aragonite phase as the major and cubic AuNPs as the minor phase. Even in dark the AuNP-decorated aragonites (especially A2) show efficacies as high 90% against gram-negative e.g., Pseudomonas putida (P. putida) bacteria. Further the AuNP-decorated aragonites (A3) show anti-biofilm capability of as high as about 20% against P. putida. Most importantly the AuNP-decorated aragonites (A3) offer anti-cancer efficacy of as high as 53% while those of A1, A2, and A4 are e.g., 26%, 46% and 37%, respectively. For the very first time, based on detailed investigations, the mechanisms behind such advance antibiofilm and anticancer activities are linked to the generation of excess labile toxic reactive oxygen species (ROS). Thus, these materials show enormous potential as futuristic, multi-functional biomaterials for anti-bacterial, anti-biofilm and anti-cancer applications.